Some kinetic properties of arginase in the sheep spleen tissue

In this study, some kinetic properties of arginase in the sheep spleen tissue was been optimized at first time in our laboratory.Its was found to be preincubation temperature 58 °C, preincubation period 13 minutes, incubation period 10 minutes and optimum pH 9.5 for sheep spleen tıssues. Enzyme achieved its highest activity at 2.25 mM MnCl2 concentration. Consequently, ıt was determined that Mn+2 ions and preincubation at 58 °C were essential for the activation of the enzyme. Km of arginase in sheep spleen tissue for arginine were determined tobe 6 mM.L- amino acids, such as L- ornithine and L- lysine inhibited the enzyme activity non-competitively. Among guanidino compounds L- canavanine inhibited the enzyme non-competitively.EDTA, NEM, p-CMBA and methylene blue were reduced arginase activity of the sheep spleen tissue. The enzyme activity was inhibited competitively by EDTA and non-competitively by the others. It was determined that approximately 50% percent of arginase in sheep spleen tissue was localized in the cell nucleus and the remaining one in the cell cytoplasm.It was investigated that methylene blue was effected on the arginase activation in different light and were determined that methylene blue, light and MnCl2 effect photoinactivation of arginase in the sheep spleen tissue.Key Words: Arginase, kinetic properties, sheep spleen tissue.